• 한국유전체학회:학술대회논문집
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• 한국유전체학회 2003년도 The 12th Korea Genome Conference
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• pp.44.2-44.2
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• 2003

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2008년도 International Meeting of the Microbiological Society of Korea
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• pp.37-37
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• 2008

• 대한미생물학회지
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• 제22권2호
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• pp.125-130
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• 1987

The role of enteropathogenic Escherichia coli(EPEC) was evaluated in a group of children with endemic diarrhea admitted to Hanyang University Hospital in Seoul, Korea. EPEC was detected in fecal samples of 23% of 100 cases and 4.5% of 44 concurrent control children. The most commonly isolated EPBC strains were serogroups $O_{18a}O_{18c}:K_{77},\;O_{86a}:K_{61},\;O_{119}:K_{69},\;and\;O_{128}:K_{70}$. On testing for enterotoxin production, 6(26%) strains were isolated from 17% of the 100 diarrheal children and in 4.5% of the 44 well controls(P<0.05). Our study supports the concept that EPEC may be an important cause of endemic diarrheas in Korea.

• 대한미생물학회지
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• 제21권4호
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• pp.417-422
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• 1986

The specimens were collected from 89 diarrheal patients who had visited Pusan National University Hospital from June to September 1985. They were cultured and tested for the bacteriological identification of causative agents. In this study we identified 5 strains of Salmonella species, 5 strains of Shigella species, 2 strains of Y. enterocolitica, and 17 strains of enteric pathogenic E. coli. Enteric pathogenic E. coli were classified into enterotoxigenic E. coli, enteropathogenic E. coli, and enteroinvasive E. coli by serological type. We tried to isolate V. cholerae and V. parahaemolyticus too but we cannot find them out.

• 한국미생물·생명공학회지
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• 제16권2호
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• pp.111-118
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• 1988

유기산 생산균인 L. casei Y, Str. faecium C, Str. faecalis, Cl. butyricum M, B. toyoi를 사료첨가제와 발효유로부터 분리 확인하여 이들 균주가 자돈의 대장균증 설사를 유발시키는 E. coli $A_2$, E. coli G$_7$에 대하여 in vitro에서는 어떤 항균효과를 나타내는지 조사한 결과를 요약하면 다음과 같다. 1. L. casei Y, Str. faecium C, Str. faecalis, B. toyoi Cl. butyricum M을 각각 배양한 BL broth 3일 배양액은 모두 E. coli $A_2$와 E. coli G$_7$에 대하여 항균효과를 나타내었고, 이들 배양액을 E. coli $A_2$와 E. coli G$_7$에 대한 발육 Disc 확산시험 결과 그 저지환 직경은 각각 15mm와 17mm, 14mm와 15mm, 13mm와 14mm, 11mm와 13 mm, 10mm와 12mm 였다. 2. 유기산 생산 능력이 우수한 균일수록 E. coli $A_2$와 E. coli G$_7$에 대한 항균력이 높게 관찰되었으며, L. casei Y와 Str. faecium C가 이들 두 대장균에 대하여 높은 항균력을 나타내었다. 3. 유기산 생성균과 대장균(E. coli $A_2$, E. coli G$_7$)을 BL broth 에 혼합 배양할 때 E. coli $A_2$와 E. coli G$_7$은 배양액의 pH가 5.0 이하일 때 생육억제 되었고, pH 4.5 이하였을 때 사멸되었다. 4. 생성된 유기산은 배양액의 pH를 저하시킴과 동시에 항균성 물질로 직접 작용하여 E. coli $A_2$와 E. coli G$_7$의 생육저해 또는 사멸을 유도하였다. 5. E. coli $A_2$가 E. coli G$_7$보다 유기산 생산균의 대사산물에 대하여 더 높은 내성을 갖고 있었다.

• 대한수의학회지
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• 제28권1호
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• pp.67-73
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• 1988

This study was conducted to isolate etiological agents from the 103 scouring piglets in Gyeongnam area and also carried out antimicrobial drug susceptibility test and epidemiogical served. The incidence of scouring piglet was most prevalent as 81.6% in the age of 2 to 4 weeks after birth, while the rate was less than 10% in the age of 5 to 6 weeks and under 1 week after birch. When compared the isolation frequency of the each etiological agent, enteropathogenic E. coli was most prevalent as 46.6%, thermophilic Campylobacter 26.2% and Salmonellae was 8.7% in order. In the OK serotyping for 117 isolates of enteropathogenic E. coli, type 0141 : K85 (20.5%), 0157:K88ac(14.5%), 0138:K81 and 0149:K91 (13.3%) were encountered most frequently. In the biotyping for 27 isolates of thermophilic Campylobacter, most strains of C. jejuni were belong to type I (50.0%) and II (25.0%), and most strains of C. coli were belong to biotype I (78.9%). In the serotyping for 9 strains of Salmonellae, 3 strains were grouped as D, 2 strains as C. and each 1 strain was group B and E. The other 2 strains were untypable. The 117 isolates of enteropathogenic E. coli were resistant more than 90% to erythromycin, penicillin, tetracycline and streptomycin, wherease about 90% of the isolates were sensitive to kanamycin and gentamicin. In the case of Salmonellae, all of the isolates were resistant to penicillin, but about 89% of the isolates were sensitive to gentamicin and colistin. All of C. jejuni and C. coli isolates were resistant to cephalothin, but more than 89% of C.jejuni and C. coli were sensitive to kanamycin and gentamicin.

• Journal of Microbiology
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• 제42권2호
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• pp.103-110
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• 2004

In order to understand the molecular basis of selective expression of stationary-phase genes by RNA polymerase containing$\sigma$$\^$38/ (E$\sigma$$\^$38/) in Escherichia coli, we examined transcription from the stationary-phase promoters, katEP, bo1AP, hdeABP, csgBAP, and mcbP, in vivo and in vitro. Although these pro-moters are preferentially recognized in vivo by E$\sigma$$\^$38/, they are transcribed in vitro by both E$\sigma$$\^$38/ and E$\sigma$$\^$70/ containing the major exponential $\sigma$, $\sigma$$\^$70/. In the presence of high concentrations of glutamate salts, how-ever, oldy E$\sigma$$\^$38/ was able to efficiently transcribe from these promoters, which supports the concept that the promoter selectivity of $\sigma$$\^$38/-containing RNA polymerase is observed only under specific reaction con-ditions. The examination of 6S RNA, which is encoded by the ssr1 gene in vivo, showed that it reduced E$\sigma$$\^$70/ activity during the stationary phase, but this reduction of activity did not result in the elevation of E$\sigma$$\^$38/ activity. Thus, the preferential expression of stationary-phase genes by E$\sigma$$\^$38/ is unlikely the con-sequence of selective inhibition of E$\sigma$$\^$70/ by 6S RNA.

• Journal of Microbiology
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• 제43권3호
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• pp.266-271
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• 2005

In eukaryotic cells, various proteins are anchored to the plasma membrane through glycosylphosphatidylinositol (GPI). To study the biosynthetic pathways and modifications of GPI, various mutant cells have been isolated from the cells of Chinese hamster ovaries (CHO) supplemented with several exogenous genes involved in GPI biosynthesis using aerolysin, a toxin secreted from gram-negative bacterium Aeromonas hydrophila. Alpha toxin from Gram-positive bacterium Clostridium septicum is homologous to large lobes (LL) of aerolysin, binds GPI-anchored proteins and possesses a cell-destroying mechanism similar to aerolysin. Here, to determine whether alpha toxins can be used as an isolation tool of GPI-mutants, like aerolysin, CHO cells stably transfected with several exogenous genes involved in GPI biosynthesis were chemically mutagenized and cultured in a medium containing alpha toxins. We isolated six mutants highly resistant to alpha toxins and deficient in GPI biosynthesis. By genetic complementation, we determined that one mutant cell was defective of the second subunit of dolichol phosphate mannose synthase (DPM2) and other five cells were of a putative catalytic subunit of inositol acyltransferase (PIG-W). Therefore, C. septicum alpha toxins are a useful screening probe for the isolation of various GPI-mutant cells.

• Journal of Veterinary Science
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• 제23권2호
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• pp.28.1-28.18
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• 2022

Enteropathogenic Escherichia coli (EPEC) is a major cause of infantile diarrhea in developing countries. However, sporadic outbreaks caused by this microorganism in developed countries are frequently reported recently. As an important zoonotic pathogen, EPEC is being monitored annually in several countries. Hallmark of EPEC infection is formation of attaching and effacing (A/E) lesions on the small intestine. To establish A/E lesions during a gastrointestinal tract (GIT) infeciton, EPEC must thrive in diverse GIT environments. A variety of stress responses by EPEC have been reported. These responses play significant roles in helping E. coli pass through GIT environments and establishing E. coli infection. Stringent response is one of those responses. It is mediated by guanosine tetraphosphate. Interestingly, previous studies have demonstrated that stringent response is a universal virulence regulatory mechanism present in many bacterial pathogens including EPEC. However, biological signficance of a bacterial stringent response in both EPEC and its interaction with the host during a GIT infection is unclear. It needs to be elucidated to broaden our insight to EPEC pathogenesis. In this review, diverse responses, including stringent response, of EPEC during a GIT infection are discussed to provide a new insight into EPEC pathophysiology in the GIT.

• Journal of Microbiology
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• 제45권6호
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• pp.558-565
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• 2007

Using microarray analysis, we determined those Salmonella genes induced at the entry of stationary phase, and subsequently discovered that uncharacterized yliH was induced most dramatically. We set out to establish the molecular mechanism underlying the stationary phase induction of yliH under the standard culture condition, LB with vigorous aeration, by analyzing its promoter activity in various mutant backgrounds, lacking stationary phase ${\sigma}$, $RpoS^-$, or stringent signal molecules ppGpp, ${\Delta}relA$ ${\Delta}spoT$. It was found that the stationary phase induction of yliHp was partially dependent on rpoS but entirely dependent on ppGpp. DNA sequence analysis revealed that the Salmonella yliH gene is composed of 381 base-pair nucleotides, with overall amino acid sequence revealing 76.38% amino acid identity and 88.98% similarity with Escherichia coli yliH, although no motif from data base was noted for its possible role. Recently however, it has been reported that yliH in E. coli was implicated in biofilm formation and motility by repressing these activities (Domka et al., 2006). We have constructed a mutant Salmonella deleting yliH gene by allele replacement and examined its phenotype, and found that the yliH in Salmonella more or less affects motility and adherence by enhancing these activities. The effect on biofilm formation in Salmonella was uncertain. Moreover, addition of cloned yliH of E. coli into Salmonella did not reduce motility or adherence. Taken together, it appears that the pathways implicating yliH for biofilm formation and motility in E. coli and in Salmonella are somewhat different.